Gaseous discharge apparatus



Oct. 1, 1935. o. T. M ILVAINE 2,016,172

GASEOUS DiSCHARGE APPARATUS Original Filed Oct. 12, 1929 if 7 T i gmnntoz MI ha k Patented Oct. 1, 1935 PATENT OFFICE GASEOUS DISCHARGE APPARATUS Oran T. Mcllvaine, St.

Charles, 111., assignor to McIlvaine Patent Corporation, St. Charles, 111., a corporation of Delaware Application October 12, 1929, Serial No. 399,283 Renewed June 14, 1935 13 Claims.

This invention relates to an improvement in gaseous discharge apparatus.

The invention is designed to be used in connection with neon tubes or the like, as are commonly employed now in advertising signs, and it relates principally to the electrode for such tubes. Instead of using the usual metal electrode, an improvement is made in the tube so as to keep the electrode from sputtering or depositing on the interior of the tube, which in turn cleans up the gas in the tube by its getter action.

The electrodes now used, if the current density is too high, causes metal to be deposited on the inside of the tube, with the above undesirable result.

With this invention, any sputtering which takes place merely moves metal from one part of the electrode to another with no resultant decrease of gas pressure, so that there is no harm caused from the sputtering.

In the accompanying drawing:

Figs. 1 to 4 represent sectional views through discharge tubes of this character, showing modifications of the invention.

In the form shown in Fig. 1, the tube is designated generally by the numeral I and is provided with a metal coating 2, plated on the inner wall of the tube I, which coating acts as the electrode and is connected with a lead wire 3, which extends through the end of the tube. This metallic coating 2 may be of any desired metal found suitable for the purpose. This keeps the electrode from sputtering or depositing on the interior of the tube or cleaning up the gas in the tube by its getter action. Any sputtering which takes place in my improved tube merely moves metal from one part of the electrode to another, with no resultant decrease of gas pressure.

A gas directing tube 4, sealed in the tube I, may be used, if found desirable, to prevent the disruptive discharge which causes the deposit on the inside of the tube and to confine the discharge to the inside of the electrode. This tube 4 is closer to the electrode 2 than the mean free path of the electrons.

In the form shown in Fig. 2, a hollow or tubular electrode 5 may be disposed in the tube I and like the metallic coating 2 may be of any suitable or desirable metal, such as tungsten, nickel, copper, iron, or carborundum, or any alloys or compounds of these, or other metals found suitable for the purpose.

This electrode 5 is sealed in the tube I, as shown in Fig. 2, with a small gas directing tube 6 extending into the hollow electrode 5 and fitting rather closely to the inside surface of the electrode and closer than the mean free path of the electrons. The wall of the tube itself is spaced very close to the outside of the electrode, being approximately of the mean free path, distance 5 away. Th s prevents the disruptive discharge which causes the deposit on the inside of the tube. The gas directing tube 6 projecting into the end of the electrode confines the discharge to the inside of the electrode where no harm is caused 10 from the sputtering.

' In the form shown in Fig. 3, this sputtering of the electrode may be prevented by coating the surface of the tube I close to the electrode 5, with a highly negative element, such as phosphorus 15 or similar compounds. This coating is designated generally by the numeral I.

Still another method of preventing evaporation of the metal electrode is by using an electrode of iron or the like with the external surface 20 enameled as at 8 in Figure 4, to prevent the evaporation and to confine the discharge to the inside of the electrode.

I claim:

1. A gaseous discharge tube containing inert 5 gas and having a hollow electrode within the discharge tube, and a directing tube projecting into said electrode for directing the gas into the electrode.

2. A gaseous discharge tube for containing inert 30 gas and comprising a hollow electrode within the discharge tube, said electrode having one end thereof approximately closed, and a directing tube separate from the wall of the discharge tube and close enough thereto to prevent dis- 35 charge around said directing tube, said directing tube projecting into said electrode for directing the gas into the electrode.

3. A gaseous discharge tube for containing inert gas and having a hollow tubular electrode sealed 40 within the discharge tube, said electrode having one end thereof closed and being adapted to receive the gas through the opposite open end, and a directing tube projecting into said electrode for directing the gas into the electrode.

4. A gaseous discharge tube for containing inert gas and having a hollow tubular electrode sealed within the discharge tube, said electrode having one end thereof closed and being adapted to receive the gas through the opposite open end, and 50 a directing tube projecting into said electrode for directing the gas into the inside of the electrode approximately at the center.

5. A gaseous discharge tube containing inert gas or gases, and having a coating on the inside 55 glass wall of the tube, in proximity to the electrode thereof, composed of an electro negative material.

6. A gaseous discharge tube containing inert gas or gases, and havinga hollow electrode therein, one end of which is closed. the other end open and facing the discharge chamber and into which electrode projects a directing tube, the sides of said directing tube being closer to the inside 01' the electrode than the mean free path oi the electrons.

7. A gaseous discharge tube containing inert gas or gases and having for its electrode a metallic coating on the inside wall thereof, and a directing tube extending into the hollow space formed by the walls that are coated, the end or said directing tube facing the discharge chamber having its edges closer to the glass walls of the tube than the mean free path of the electrons.

8. A gaseous discharge-tube containing inert .gas or gases and having a hollow electrode therein, one end of which is open and receives the end of a directing tube, the edges of said directing tube fitting the inside 01' the electrode closer than the mean free path or the electrons, the other end of the directing tube being closer to the walls 01' the discharge tube than the mean free path of the electrons.

9. A gaseous discharge tube containing inert gas and having a hollow electrode therein, and

' a gas directing tube projecting into said electrode,andbeingclosertotheelectrodethanthe meaniree'pathortheeiectrons.

l0. Agaseous dischargetube'cosnprisinganen- V pc aving a hollow electrode connected therewith,andagasdirectingtubeseparateiromthe 5 envelope and projecting intos'aid electrode and havingan endilaredlaterallytothe side wallsot the envelope, said directing tube being closer in thewailsottheenvelopethanthemeaniree P th of the electrons. in

11. A gaseous discharge tube comprising an envelope tor inert gas and having a hollow electrode therein, and a gas directing tube having an end flaredlaterallyandjolningthesidewallsoithe envelope and the other end projecting into the is electrode and spaced therefrom a distance approximately less than the mean free path or the electrons.

12. A gaseous discharge tube containing inert gascrgaseaandhavingacoatingontheinsidezo wall of the tube in proximity to the electrode thereof, composed substantially oi phosphorus.

13. A gaseous discharge tube having glass walls,

' a hollow electrode for said tube having tubular walls and an enlarged open end and a gas di- 26 recting tube within the discharge tube and separate from the glass walls thereof, being arranged closer to the glass walls than the mean tree path or the electrons, said directing tube being arranged to direct gas into the electrode. 30

ORAN T. McILVAINE. 

